1. Field of the Invention
The present invention relates to a receiver, and more particularly, to a receiver for simultaneously displaying a high definition (HD) signal and a standard image signal which have different display formats and/or different frame rates, and a method thereof.
2. Description of the Related Art
MP @ML (main profile at main level) video decoders, which have been proposed by the moving picture experts group (MPEG) of the International Standards Organization for a recent completely-developed two dimensional moving picture decoding and transmission technique, have a resolution of the same level as that of standard definition television (SDTV) and have been widely used with the advent of digital broadcasting and various multimedia apparatuses. Also, the development of high definition television (HDTV) having a MP @HL (main profile at high level) resolution has begun, and some HDTVs having a MP @HL resolution have already seen common use.
In the near future, Europe will also start HDTV broadcasting in a digital format. When a United States-type display format is used, new HDTV receivers will be required for viewers to watch the HDTV broadcasting in a digital format, so that existing NTSC- or PAL-format TV may be of no use. To prevent this problem, a set-top box must be installed in an NTSC- or PAL-format TV to receive HD signals. That is, at the start of digital HD broadcasting, the coexistence of the digital HD broadcasting with existing NTSC- or PAL broadcasting cannot be avoided. Thus, HDTV receivers must be able to receive NTSC/PAL signals as well as HD signals, and existing NTSC TVs and PAL TVs must be able to receive the outputs of the HDTV receivers and display them on a screen.
Accordingly, when nations which use PAL-format broadcasting introduce a United States-type digital HD broadcasting standard (for example, 1920 pixelsxc3x971080 linesxc3x9760 Hz interlace image or 1280 pixelsxc3x97720 linesxc3x9760 Hz progressive image), a set-top box or an HDTV receiver must have a structure capable of converting an HD signal to a PAL signal to process the two types of broadcasting signals, since the PAL broadcasting signal has a 50 Hz vertical frequency which is different from that of the United States-type digital HD broadcasting standard of 60 Hz. That is, the two types of broadcasting signals have different frame rates. For example, when it is intended for an HDTV to use a video cassette recorder (VCR) for recording a currently-used PAL broadcasting signal or to display a received HD signal on a PAL broadcasting standard receiver while simultaneously displaying the HD signal, or when it is intended for a PAL receiver, including a set-top box, to display an HD signal, the HDTV receiver or the PAL receiver including a set-top box should have a structure capable of converting an HD signal to a PAL signal.
An objective of the present invention is to provide a receiver for simultaneously displaying a high definition (HD) signal and a standard definition (SD) image signal which have different display formats and/or different frame rates.
Another objective of the present invention is to provide a method of simultaneously displaying an HD signal and an SD image signal which have different display formats and/or different frame rates on a TV including a set-top box or on a receiver such as a high definition television (HDTV).
Accordingly, to achieve the first objective, the present invention provides a receiver including: a signal generator for generating a first vertical synchronous signal for a high definition (HD) image, a first field identification signal for coping with a case in which an HD image is an interlace image, a second vertical synchronous signal for a standard image, and a second field identification signal for a standard image; a first display processor for processing a received HD decoded image to an HD display format according to the first vertical synchronous signal and the first field identification signal; and a second display processor for down-sampling the HD decoded image using the first and second vertical synchronous signals and the first and second field identification signals, and providing a standard definition (SD) image signal having a standard display format that is different from the HD display format.
To achieve the second objective, the present invention provides a method of simultaneously displaying signals having different display formats and/or different frame rates, the method including the steps of: (a) decoding a received high definition (HD) image and providing an HD decoded image; (b) processing the HD decoded image to an HD display format according to a first vertical synchronous signal and a first field identification signal for coping with the case in which the HD image is an interlace image; and (c) down-sampling the HD decoded image using the first vertical synchronous signal for an HD image, the first field identification signal for an HD image, a second vertical synchronous signal for a standard image, and a second field identification signal for a standard image, and providing a standard image signal having a standard display format that is different from the HD display format.